Effects of Flushings with an Acidic Calcium Phosphate Solution on Fluoride Binding and Caries in Rat Teeth

Abstract

This investigation, comprising three studies, measured the effects of flushing with an acidic calcium phosphate solution (CPS) on the cariostatic benefits of fluoride. In the first two studies, the rats received fluoride in the drinking water (2.5 ppm F) after initiation of the caries challenge. In contrast, in the third study, the animals received treatments as oral flushing before initiation of the cariogenic challenge. In all three studies, rats that received CPS in conjunction with fluoride exhibited a numerically lower mean caries score than those that received H₂O in conjunction with fluoride. Moreover, in the third study, the group receiving oral flushing of CPS followed by NaF (10,000 ppm F) for 3 successive days exhibited a significantly lower incidence of dental caries and higher concentration of enamel-bound fluoride than did the group treated with a H₂O-NaF sequence. A significant negative association (––0.65) between fluoride and caries was noted when the dentition of all rats in the third study were considered.

Effects of an Acidic Calcium Phosphate Solution and the Intraoral Fluoride-Releasing Device on Dental Caries and Fluoride Uptake in Rats

“…This pattern of con tact is affirmed by the distribution of CPS-induced dental staining noted in the unassigned animals. It is also consistent with the observations of Weathercll et al (1981) and our previous studies [Shern et al, 1984a[Shern et al, , 1987, Thus, the AgNO, method should prove useful in studying the CPS distribution and the sub sequent conversion of its reaction products to apatite.…”

“…In the first study the incidence of dental caries was substantially less than that noted previously [Shern et al, 1984a[Shern et al, , 1987Schreiber et al, 1988). Presumably, the reduced incidence resulted because the cariogenic challenge was postponed until after the treatment pe riod, thus allowing the natural resistance of the rats' teeth to increase.…”

“…Presumably, the reduced incidence resulted because the cariogenic challenge was postponed until after the treatment pe riod, thus allowing the natural resistance of the rats' teeth to increase. This reduced susceptibility and re sultant lower range of caries scores probably contrib uted to the insignificant negative correlation between the caries score and the level of enamel-bound fluo ride, i.e., r = -0.20, compared with r = -0.49 and r = -0.65, noted previously [Shern et al, 1987;Schreiber et al, 1988].…”

“…The CPS creates a surface rich in dicalcium phosphate di hydrate that binds readily with fluoride to form a fluoridc-rich apatite. CPS and fluoride solutions applied sequentially produced high levels of fluorapatite with no morphologic change in the tooth surface in vitro [Chow and Brown, 1975], in rats [Shern et al, 1979[Shern et al, , 1984a[Shern et al, , 1987Schreiber et al, 1988] and in humans [Chow et al, 1981].…”

“…Results of rat studies also indicated that enamel-bound fluoride impedes the development of enamel caries. In a rat study designed to minimize the presence of fluoride borne by the oral fluids, a nega tive association (r = -0.65) was detected between the incidence of caries and the level of fluoride in the outer layers of molar enamel [Shern et al, 1987].…”